; a
(print (eql (+ (- 5 1) (+ 3 7)) 14))
; b
(print (equal '(1 5) (list 1 (+ 2 3))))
; c
(print (eql 7 (if (listp 1) (+ 1 2) (+ 3 4))))
; d
(print (equal '(nil 3) (list (and (listp 3) t) (+ 1 2))))
